The Role of Ribonucleic Acids in the Organization and Functioning of Ribosomes of E. coli

Bogdanov, Alexei A.; Копылов, А. М.; Shatsky, Ivan N.

doi:10.1007/978-1-4615-7948-9_2

Cited by 16 publications

(4 citation statements)

References 122 publications

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“…This common property could be the presence of RNA nucleotides exposed on the surface of the RNP complexes, a suggestion extrapolated from the predictions of Clawson and Smuckler who showed that the amount of high energy phosphate expended by isolated nuclei was proportional to the number of nucleotides released as RNP (14). A substantial fraction ("~30% based on RNase accessibility) of RNA in the ribosome is exposed in short stretches (8,10). Similarly, Dworetzkey and Feldherr showed that colloidal gold particles coated with either tRNA, 5S RNA, or poly(A) were also transported from nuclei in a concentration-dependent, nuclear pore-mediated process (20).…”

Section: Discussionmentioning

confidence: 97%

Cytoplasmic transport of ribosomal subunits microinjected into the Xenopus laevis oocyte nucleus: a generalized, facilitated process.

Bataillé

Helser

Fried

1990

The Journal of Cell Biology

128

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Abstract. To study the biochemistry of ribonucleoprotein export from the nucleus, we characterized an in vivo assay in which the cytoplasmic appearance of radiolabeled ribosomal subunits was monitored after their microinjection into Xenopus oocyte nuclei. Denaturing gel electrophoresis and sucrose density gradient sedimentation demonstrated that injected subunits were transported intact. Consistent with the usual subcellular distribution of ribosomes, transport was unidirectional, as subunits injected into the cytoplasm did not enter the nucleus. Transport displayed properties characteristic of a facilitated, energy-dependent process; the rate of export was saturable and transport was completely inhibited either by lowering the temperature or by depleting nuclei of ATP; the effect of lowered temperature was completely reversible. Transport of injected subunits was likely a process associated with the nuclear pore complex, since export was also inhibited by prior or simultaneous injection of wheat germ agglutinin, a lectin known to inhibit active nuclear transport by binding to N-acetyl glucosamine-containing glycoproteins present in the NPC (Hart, G. W., R. S. Haltiwanger, G. D. Holt, and W. G. Kelly. 1989. Annu. Rev. Biochem. 58:841-874). Although GIcNAc modified proteins exist on both the nuclear and cytoplasmic sides of the nuclear pore complex, ribosomal subunit export was inhibited only when wheat germ agglutinin was injected into the nucleus. Finally, we found that ribosomal subunits from yeast and Escherichia coli were efficiently exported from Xenopus oocyte nuclei, suggesting that export of some RNP complexes may be directed by a collective biochemical property rather than by specific macromolecular primary sequences or structures.T HE assembly of ribosomes in eukaryotic cells is a process that requires transfer of macromolecules into and out of the nucleus (33). Ribosomal proteins, synthesized in the cytoplasm, enter the nucleus and assemble with nascent rRNA to form a preribosomal particle. Through a series of maturation steps involving endonucleolytic cleavage of the primary rRNA transcript and further addition of specific ribosomal proteins, the preribosomal particle splits into partially completed 40S and 60S subunits that contain the nearly mature 18S and 28S:5.8S rRNAs, respectively. The pre-60S subunit also acquires a 5S rRNA molecule by addition of a separate 5S-containing RNP (51). Eventually, the 40S and 60S subunits exit the nucleus into the cytoplasm where they assemble with additional ribosomal proteins. While much is known about mechanisms that regulate synthesis of individual ribosomal components (4, 56), we envision equally important mechanisms that promote efficient assembly of ribosomal components. Therefore, we wish to determine the driving forces that bring about exchange of ribosomal components between the nucleus and cytoplasm.Mechanisms of macromolecular transport across the nuclear-cytoplasmic boundary have been the focus of much recent research. A conspicuous structure spanning...

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Section: Discussionmentioning

confidence: 97%

Cytoplasmic transport of ribosomal subunits microinjected into the Xenopus laevis oocyte nucleus: a generalized, facilitated process.

Bataillé

Helser

Fried

1990

The Journal of Cell Biology

128

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“…The small ribosomal subunit of Escherichia coli consists of 1542-nucleotides-long 16S rRNA and 20 different medium-size proteins. The proteins that are the first to bind to the 16S rRNA (S4, S7, S8, S15) resulting in the formation of the so-called “structural core” of a small subunit play a crucial role during the self-assembly of the 30S subunit [ 6 , 7 ]. The ribosomal assembly process has come into the focus of researchers again now that the structure of the small subunit of thermophilic and mesophilic ribosomes has been identified using X-ray diffraction (XRD) analysis [8– 10 ].…”

Section: Introductionmentioning

confidence: 99%

Identification of Novel RNA-Protein Contact in Complex of Ribosomal Protein S7 and 3’-Terminal Fragment of 16S rRNA in E. coli

et al. 2012

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For prokaryotes in vitro, 16S rRNA and 20 ribosomal proteins are capable of hierarchical self- assembly yielding a 30S ribosomal subunit. The self-assembly is initiated by interactions between 16S rRNA and three key ribosomal proteins: S4, S8, and S7. These proteins also have a regulatory function in the translation of their polycistronic operons recognizing a specific region of mRNA. Therefore, studying the RNA–protein interactions within binary complexes is obligatory for understanding ribosome biogenesis. The non-conventional RNA–protein contact within the binary complex of recombinant ribosomal protein S7 and its 16S rRNA binding site (236 nucleotides) was identified. UV–induced RNA–protein cross-links revealed that S7 cross-links to nucleotide U1321 of 16S rRNA. The careful consideration of the published RNA– protein cross-links for protein S7 within the 30S subunit and their correlation with the X-ray data for the 30S subunit have been performed. The RNA – protein cross–link within the binary complex identified in this study is not the same as the previously found cross-links for a subunit both in a solution, and in acrystal. The structure of the binary RNA–protein complex formed at the initial steps of self-assembly of the small subunit appears to be rearranged during the formation of the final structure of the subunit.

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“…In spite of the substantial progress in the elucidation of primary and secondary structures of Escherichia coli 5 S, 16 S, and 23 S RNA, our knowledge of the spatial organization of rRNA in both intact ribosomal subunits and 70 S ribosomes is still very limited (for references, see [ 1,2]). In [3] we proposed a general approach to the identification of external RNA regions in ribosomal subunits.…”

Section: Introductionmentioning

confidence: 99%

Topography of RNA in the ribosome: Localization of the 3′‐end of the 23 S RNA on the surface of the 50 S ribosomal subunit by immune electron microscopy

et al. 1980

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The Role of Ribonucleic Acids in the Organization and Functioning of Ribosomes of E. coli

Cited by 16 publications

References 122 publications

Cytoplasmic transport of ribosomal subunits microinjected into the Xenopus laevis oocyte nucleus: a generalized, facilitated process.

Cytoplasmic transport of ribosomal subunits microinjected into the Xenopus laevis oocyte nucleus: a generalized, facilitated process.

Identification of Novel RNA-Protein Contact in Complex of Ribosomal Protein S7 and 3’-Terminal Fragment of 16S rRNA in E. coli

Topography of RNA in the ribosome: Localization of the 3′‐end of the 23 S RNA on the surface of the 50 S ribosomal subunit by immune electron microscopy

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